Stationary semi-solid battery module and method of manufacture

ABSTRACT

A method of manufacturing an electrochemical cell includes transferring an anode semi-solid suspension to an anode compartment defined at least in part by an anode current collector and an separator spaced apart from the anode collector. The method also includes transferring a cathode semi-solid suspension to a cathode compartment defined at least in part by a cathode current collector and the separator spaced apart from the cathode collector. The transferring of the anode semi-solid suspension to the anode compartment and the cathode semi-solid to the cathode compartment is such that a difference between a minimum distance and a maximum distance between the anode current collector and the separator is maintained within a predetermined tolerance. The method includes sealing the anode compartment and the cathode compartment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalApplication Ser. No. 61/531,927, filed Sep. 7, 2011, entitled, “BatteryManufacturing Method,” which is incorporated by reference herein in itsentirety.

BACKGROUND

Embodiments described herein relate generally to the preparation ofelectrode cells for use in electrochemical devices and more particularlyto systems and methods of using a semi-solid electrode cell in a batterymodule.

Conventional battery systems store electrochemical energy by separatingan ion source and ion sink at differing ion electrochemical potential. Adifference in electrochemical potential produces a voltage differencebetween the positive and negative electrodes, which produces an electriccurrent if the electrodes are connected by a conductive element. In aconvention battery system, negative electrodes and positive electrodesare connected via a parallel configuration of two conductive elements.The external elements exclusively conduct electrons, however, theinternal elements, being separated by a separator and electrolyte,exclusively conduct ions. The external and internal flow streams supplyions and electrons at the same rate, as a charge imbalance cannot besustained between the negative electrode and positive electrode. Theproduced electric current can be used to drive an external device. Arechargeable battery can be recharged by application of an opposingvoltage difference that drives electric and ionic current in an oppositedirection as that of a discharging battery. Accordingly, active materialof a rechargeable battery requires the ability to accept and provideions. Increased electrochemical potentials produce larger voltagedifferences between the cathode and anode of a battery, which increasesthe electrochemically stored energy per unit mass of the battery. Forhigh-power batteries, the ionic sources and sinks are connected to aseparator by an element with large ionic conductivity, and to thecurrent collectors with high electric conductivity elements.

Typical battery manufacturing involves numerous complex and costlyprocesses carried out in series, each of which is subject to yieldlosses, incurs capital costs for equipment, and includes operatingexpenses for energy consumption and consumable materials. The processfirst involves making separate anodic and cathodic mixtures that aretypically mixtures of electrochemically active ion storage compounds,electronically conductive additives, and polymer binders. The mixturesare coated onto the surfaces of flexible metal foils and subsequentlycompressed under high pressure to increase density and controlthickness. These compressed electrode/foil composites are then slittedinto sizes and/or shapes that are appropriate for the particular formfactor of the manufactured battery. The slitted electrode composites aretypically co-wound or co-stacked with interveningionically-conductive/electronically-insulating separator membranes toconstruct battery windings, i.e. “jelly rolls” or “stacks,” which arethen packaged in metal cans, flexible polymer pouches, etc. Theresulting cells can be infiltrated with liquid electrolyte that need beintroduced in a carefully controlled environment.

The stored energy or charge capacity of a manufactured battery isrelated to the inherent charge capacity of the active materials (mAh/g),the volume of the electrodes (cm³), the product of the thickness, area,and number of layers, and the loading of active material in theelectrode media (e.g., grams of active material/cubic centimeters ofelectrode media. Therefore, to enhance commercial appeal (e.g.,increased energy density and decreased cost), it is generally desirableto increase areal charge capacity (mAh/cm²) of the electrodes that areto be disposed in a given battery form factor, which depends onelectrode thickness and active material loading. Moreover, it isdesirable to increase electrical conduction between the currentcollector and the electrode material. For example, it can be desirableto increase the surface area of the current collector that is inphysical and/or electrical connection with a semi-solid electrodematerial.

Binder-free electrode formulations can exhibit a wide range ofrheological characteristics depending on their constituent types (e.g.,composition), component concentrations, manner of preparation, andelectrochemical and/or temporal history. Furthermore, in gravitationalfields and/or when subjected to shear gradients during mixing or flow,particle segregation can occur, depending on relative densities,particles shapes and sizes, and carrier fluid properties (e.g.,viscosity, and flow geometry) that can lead to non-uniformity of theelectrode formulations. Thus, a need exists for an electrode that doesnot substantially include a binder agent and for a manufacturing processthat addresses the rheological characteristics of a binder-freeelectrode.

SUMMARY

Systems and methods of using a semi-solid suspension in anelectrochemical cell are described herein. In some embodiments, a methodof manufacturing an electrochemical cell includes transferring an anodesemi-solid suspension to an anode compartment defined at least in partby an anode current collector and a separator (e.g., an ion permeablemembrane) spaced apart from the anode collector. The method alsoincludes transferring a cathode semi-solid suspension to a cathodecompartment defined at least in part by a cathode current collector andthe separator spaced apart from the cathode current collector. Thetransferring of the anode semi-solid suspension to the anode compartmentand the cathode semi-solid to the cathode compartment is such that adifference between a minimum distance and a maximum distance between theanode current collector and the ion permeable membrane is maintainedwithin a predetermined tolerance. The method includes sealing the anodecompartment and the cathode compartment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a filling technique used to fill acompartment with an electrode, according to an embodiment.

FIG. 2 illustrates a system for manufacturing an electrochemical cell,according to an embodiment.

FIG. 3 is a perspective view of a portion of injection nozzles includedin the system of FIG. 2.

FIG. 4 is a cross-sectional view of a portion of the system of FIG. 2,taken along the like X₁-X₁.

FIG. 5 is a flowchart illustrating a method of manufacturing theelectrochemical cell illustrated in FIG. 2.

FIG. 6 is a flowchart illustrating a method of manufacturing anelectrochemical cell, according to an embodiment.

FIG. 7 is a flowchart illustrating a method of manufacturing anelectrochemical cell, according to an embodiment.

FIG. 8 illustrates a system for manufacturing an electrochemical cell,according to an embodiment.

FIG. 9 is an illustration of an electrode in a first, second, and thirdconfiguration, according to an embodiment.

FIGS. 10A-10D illustrate a first electrode and a second electrode beforeand after a post-treatment, according to an embodiment.

FIG. 11 is a graph describing a rheological property, according to anembodiment.

FIGS. 12A and 12B are illustrations of a support structure included inan electrochemical cell, according to an embodiment.

FIG. 13 is an illustration of an electrochemical cell during a fillprocess, according to an embodiment.

DETAILED DESCRIPTION

Embodiments described herein relate generally to the preparation ofelectrodes for use in electrochemical devices and more particularly tosystems and methods of using a semi-solid suspension (also referred toherein as “slurry”) in a battery module. In some embodiments,electrochemical devices (e.g., batteries) manufactured directly with asemi-solid suspension avoid the use of conventional binding agents andthe electrode casting step altogether. Some benefits of this approachinclude, for example: (i) a simplified manufacturing process with lessequipment (i.e., less capital intensive), (ii) the ability tomanufacture electrodes of different thicknesses and shapes (e.g., bychanging an extrusion die slot dimension), (iii) processing of thicker(>100 μm) and higher charge capacity (mAh/cm²) electrodes, therebydecreasing the volume, mass, and cost contributions of inactivecomponents with respect to active material, and (iv) the elimination ofbinding agents, thereby reducing tortuosity and increasing ionicconductivity of the electrode. Examples of battery architecturesutilizing semi-solid suspensions are described in International PatentPublication No. WO 2012/024499, entitled “Stationary, Fluid RedoxElectrode,” and International Patent Publication No. WO 2012/088442,entitled “Semi-Solid Filled Battery and Method of Manufacture,” theentire disclosures of which are hereby incorporated by reference.

The cathode and/or anode materials described herein can be a flowablesemi-solid or condensed liquid composition. A flowable anodic semi-solid(also referred to herein as “anolyte”) and/or a flowable cathodicsemi-solid (also referred to herein as “catholyte”) are/is comprised ofa suspension of electrochemically-active agents (anode particulatesand/or cathode particulates) and, optionally, electronically conductiveparticles (e.g., carbon). The cathodic particles and conductiveparticles are co-suspended in an electrolyte to produce a catholytesemi-solid. The anodic particles and conductive particles areco-suspended in an electrolyte to produce an anolyte semi-solid. Thesemi-solids are capable of flowing in response to an applied pressuredifferential, gravitational field, or other imposed acceleration field,that produces exerts or produces a force on the semi-solid, andoptionally, with the aid of mechanical vibration.

As used herein, the term “semi-solid” refers to a material that is amixture of liquid and solid phases, for example, such as a particlesuspension, colloidal suspension, emulsion, gel, or micelle.

As used herein, the terms “condensed ion-storing liquid” or “condensedliquid” refers to a liquid that is not merely a solvent, as in the caseof an aqueous flow cell catholyte or anolyte, but rather, that is itselfredox-active. Of course, such a liquid form may also be diluted by ormixed with another, non-redox-active liquid that is a diluent orsolvent, including mixing with such a diluent to form a lower-meltingliquid phase, emulsion or micelles including the ion-storing liquid.

As used in this specification, the terms “about” and “approximately”generally include plus or minus 10% of the value stated. For example,about 5 would include 4.5 to 5.5, approximately 10 would include 9 to11, and about 100 would include 90 to 110.

As used herein, the terms “activated carbon network” and “networkedcarbon” relate to a general qualitative state of an electrode. Forexample, an electrode with an activated carbon network (or networkedcarbon) is such that the carbon particles within the electrode assume anindividual particle morphology and arrangement with respect to eachother that facilitates electrical contact and electrical conductivitybetween particles. Conversely, the terms “unactivated carbon network”and “unnetworked carbon” relate to an electrode wherein the carbonparticles either exist as individual particle islands or multi-particleagglomerate islands that may not be sufficiently connected to provideadequate electrical conduction through the electrode.

In some embodiments, a method of manufacturing an electrochemical cellincludes transferring an anode semi-solid suspension to an anodecompartment defined at least in part by an anode current collector andan ion permeable membrane spaced apart from the anode collector. Themethod also includes transferring a cathode semi-solid suspension to acathode compartment defined at least in part by a cathode currentcollector and the ion permeable membrane spaced apart from the cathodecurrent collector. The transferring of the anode semi-solid suspensionto the anode compartment and the cathode semi-solid to the cathodecompartment is preferably performed such that a difference between aminimum distance and a maximum distance between the anode currentcollector and the ion permeable membrane is maintained within apredetermined tolerance. The method includes sealing the anodecompartment and the cathode compartment.

In some embodiments, a method of manufacturing an electrochemical cellincludes disposing an injection nozzle in an electrode cell (e.g., ananode and/or cathode cell) that is defined, at least in part, by acurrent collector and an ion permeable membrane. A semi-solid suspensionelectrode material can be transferred to the electrode compartmentthrough the injection nozzle. The method further includes withdrawingthe injection nozzle from the electrode compartment during at least aportion of the transferring.

In some embodiments, a method of manufacturing an electrochemical cellincludes disposing an anode injection nozzle in an anode compartmentthat is defined, at least in part, by an anode current collector spacedapart from an ion permeable membrane. An anode semi-solid suspension canbe transferred to the anode compartment through the anode injectionnozzle and the anode injection nozzle can be withdrawn from the anodecompartment during at least a portion of the transferring. The methodfurther includes disposing a cathode injection nozzle in a cathodecompartment that is defined, at least in part, by a cathode currentcollector spaced apart from an ion permeable membrane. A cathodesemi-solid suspension can be transferred to the cathode compartmentthrough the cathode injection nozzle and the cathode injection nozzlecan be withdrawn from the cathode compartment during at least a portionof the transferring.

In some embodiments, a method of manufacturing an electrode for anelectrochemical cell includes discharging semi-solid suspensionelectrode material through an extrusion die slot to form an electrode.The formed electrode can be transferred to an electrode compartmentdefined, at least in part, by a current collector and an ion permeablemembrane. The method further includes transferring an electrolyte to theelectrode compartment.

In some embodiments, a method of manufacturing an electrode for anelectrochemical cell includes filling an electrode compartment defined,at least in part, by a current collector and an ion permeable membranewith an electrode material in powdered form. The electrode compartmentcan be placed in an electrolyte vapor-containing environment such thatat least a portion of the gaseous electrolyte condenses to liquid formin the electrode compartment. The method further includes sealing theelectrode compartment.

In some embodiments, an anolyte and a catholyte are introduced into anelectrode cell via ports disposed along an edge of the electrode cell.For example, FIG. 1 is an illustration of a system 100 for filling abattery cell 110, according to an embodiment. The battery cell 110 canbe a bipolar cell consisting of an anode cell 111, a cathode cell 121,and a separator 130 disposed therebetween. The anode cell 111 and thecathode cell 121 are each bounded by a current collector (not shown inFIG. 1) spaced apart from the separator 130. In this manner, the anodecell 111 and the cathode cell 121 each form a compartment (not shown inFIG. 1). The anode compartment of the anode cell 111 is configured toreceive an anolyte slurry and the cathode compartment of the cathodecell 121 is configured to receive a catholyte slurry. The separator 130can be, for example, an ion-permeable membrane.

The battery cell 110 can be, for example, substantially rectangular (asshown in FIG. 1), having a relatively large length L and relativelysmall thickness T. More specifically, the anode cell 111 and the cathodecell 121, that at least partially comprise the battery cell 110, arerelatively long and thin, thus, the anode compartment and the cathodecompartment are relatively long and relatively thin compartments. Insome embodiments, the length of the anode cell 111 and/or cathode cell121 can be in the range of about 5 cm to about 25 cm. In someembodiments, the length of the anode cell 111 and/or cathode cell 121can be in the range of about 10 cm to about 20 cm. In some embodiments,the length of the anode cell 111 and/or cathode cell 121 can be in therange of about 15 cm to about 20 cm. In some embodiments, the thicknessof the anode cell 111 and/or cathode cell 121 can be in the range ofabout 100 μm to about 1 mm. In some embodiments, the thickness of theanode cell 111 and/or cathode cell 121 can be in the range of about 250μm to about 750 μm. In some embodiments, the thickness of the anode cell111 and/or cathode cell 121 can be about 500 μm. Thus, the anode cell111 and/or the cathode cell 121 can have a relatively high aspect ratioin the range of at least about 50 to at least about 2,500. In someembodiments, the anode cell 111 and/or the cathode cell 121 can have arelatively high aspect ratio in the range of at least about 100 to atleast about 1,200. In some embodiments, the anode cell 111 and/or thecathode cell 121 can have a relatively high aspect ratio in the range ofat least about 100 to at least about 600. In some embodiments, the anodecell 111 and/or the cathode cell 121 can have a relatively high aspectratio of at least about 50, of at least about 100, of at least about200, of at least about 300, of at least about 400, or of at least about500.

While the geometry of the anode cell 111 and the cathode cell 121 isshown in FIG. 1 as substantially rectangular, the compartments formed bythe anode cell 111 and the cathode cell 121 can have any suitablegeometry. For example, in some embodiments, the geometry of thecompartments can be polygonal (rectangular, hexagonal, etc.) or oval(elliptical, circular, etc.). Moreover, the compartments can have auniform thickness or can vary in thickness spatially along the anodecell 111 and/or cathode cell 121. In some embodiments, the anode cell111 and the cathode cell 121 can include partitions and/or supportstructure within the compartments that can provide structural support(e.g., for the current collectors and/or the separator 130) and/orfacilitate desired fluid dynamic properties. For example, in someembodiments, the anode cell 111 and/or the cathode cell 121 can includesupport pins (not shown in FIG. 1) that substantially support and/ormaintain the spacing between the current collectors and/or the separator130. In other embodiments, a current collector can be substantiallycorrugated and be configured to support the separator 130. In someembodiments, the anode cell 111 and/or the cathode cell 121 can includeother support structures such as, for example, posts or ridges. Thesupport structures can be an independent element or elements, attachedto or integral to the current collector, or attached to or integral tothe separator. In some embodiments, the support structures can beelectrically conductive and in addition to mechanically supporting theseparator 130, the support structures can enhance the electrodeconductivity, which leads to improved cell performance. In someembodiments, the support structures can be thermally conductive and areconfigured to facilitate more effective heat transfer and thermalmanagement of the cell. In some embodiments, the use of supportstructure can substantially limit deflection of, and/or spacing between,the separator 130 and/or the current collectors to within a giventolerance (e.g., +/−1%, +/−3%, +/−4%, +/−5%, or any other suitabletolerance).

The anode cell 111 includes a port 112 configured to receive a portionof a first injection tool 140 such that the anode compartment canreceive the anolyte. Similarly, the cathode cell 121 includes a port.122 configured to receive a portion of a second injection tool 140(e.g., similar or the same as the first injection tool 140) such thatthe cathode compartment can receive the catholyte. While shown as beingsubstantially circular, the anode port 112 and the cathode port 122 canbe any suitable shape, size, or configuration. For example, in someembodiments, an anode cell and/or a cathode cell can include a port thatis oriented along an edge of the cell. Furthermore, while shown as beingat different locations along the length of the cell, the anode port 112and the cathode port 122 can be positioned at substantially the samelocation along the edge of the cell.

The anolyte and catholyte can be introduced into the anode compartmentand the cathode compartment, prior to the battery cell 110 being sealed.The anolyte and the catholyte can be, for example, flowable semi-solidsor condensed liquid compositions. For example, the anolyte can be asemi-solid suspension of anode particulates and electronicallyconductive particles. Similarly, the catholyte can be a semi-solidsuspension of cathode particulates and electronically conductiveparticles. The anolyte and the catholyte can be introduced into theanode compartment and the cathode compartment, respectively, using anysuitable method. For example, the first injection tool 140 and thesecond injection tool 140 can each initiate a flow of anolyte and thecatholyte, respectively, into the compartments. The injection tools 140can be any suitable devices. For example, the injection tools 140 aresyringes configured to apply a pressure on at least a portion of theanolyte and catholyte, respectively, to facilitate a flow of theflowable semi-solids. Expanding further, in some embodiments, theinjection tools 140 can be actuated by a user supplied force, a machinesupplied force (e.g., a machine driven plunger), a gravitational force,a centrifugal force, or the like.

In some embodiments, the injection tools 140 can be intracell injectionnozzles. In such embodiments, the injection nozzle can have a geometrythat substantially corresponds to a geometry of, for example, the anodecompartment or the cathode compartment. For example, in someembodiments, the injection nozzle is a set of tubes that have beencoupled together such that an overall dimension of the set of tubessubstantially corresponds to a geometry of a compartment. In otherembodiments, the injection nozzle can have a geometry that substantiallycorresponds to a geometry of the compartment while defining a singleopening.

In embodiments wherein the injection tool 140 is an intracell injectionnozzle, at least a portion of the injection nozzles can be insertedthrough the port 112 of the anode cell 111 and/or through the port 122of the cathode cell 121 to be movably disposed within the anodecompartment and/or the cathode compartment, respectively. The injectionnozzles can be configured to be movable between a first position and asecond position such that a desired pressure is maintained within thecompartment or compartments during the introduction of the slurry (e.g.,the anolyte or the catholyte. The injection nozzle can further be influid communication with a slurry reservoir (e.g., a syringe or thelike) to deliver a flow of the slurry. In some embodiments, theintracell injection nozzle can be thermally controlled to facilitate theflow and retention of compositional homogeneity of the slurry. In someembodiments, multiple banks of injection nozzles can be similarlydisposed within adjacent electrochemical cells such that the pressurewithin a first electrochemical cell is balanced by a pressure within asecond electrochemical cell.

In some embodiments, the injection tool 140 is an extruding device. Insuch embodiments, an electrode slurry can be extruded through anextrusion slot such that the extruded slurry has a geometry thatsubstantially corresponds to the anode compartment and/or the cathodecompartment. In this manner, the extruded slurry can be transferred tothe electrode compartments. In some embodiments, an electrolyte can betransferred to the electrode compartment (e.g., via a secondaryinjection tool not shown in FIG. 1). In such embodiments, the extrudedslurry and the electrolyte can form a substantially uniform suspensionwithin the electrode compartment.

In some embodiments, the injection tool(s) 140 can be a dry feeder(e.g., a hopper, a volumetric screw feeder, a gravimetric screw feeder,or the like). In such embodiments, the dry feeder can be configured totransfer an electrode material in powdered form to the electrode cell.In some embodiments, the electrode cell (e.g., the anode cell 111 and/orthe cathode cell 121) can be placed in fluid communication with anelectrolyte reservoir that contains an electrolyte at a substantiallyhigher temperature, i.e. in a gas phase, than a temperature within theelectrode cell, which may be maintained at a cooler temperature. In thismanner, a portion of the electrolyte can condense from a gas phase intoa liquid phase within the electrode chamber such that the powderedelectrode and the electrolyte can mix. In some embodiments, theelectrode cell can be disposed (e.g., at least partially) within anelectrolyte vapor-containing environment.

In some embodiments, the transferring of the flowable semi-solids(anolyte and/or catholyte) can be assisted by mechanical vibration,sonic agitation, gravitational force, or shearing. The flow assistancecan occur before, during, or after the transfer of the electrodematerials into the compartments to decrease viscosity, promotesuspension stability, overcome and/or augment forces inducing flow, andmaintain an activated carbon network. In some embodiments, vibrationand/or sonication can be used continuously during a fill process. Inother embodiments, vibration and/or sonication can be usedintermittently during a fill process. For example, vibration and/orsonication can be used after a given portion of an electrode slurry istransferred to a compartment. In some embodiments, the vibration and/orsonication process can be utilized serially after multiple portions ofthe slurry are transferred to the cavity.

In some embodiments, a vacuum can be applied to a portion of anelectrode compartment. The vacuum can apply a suction force within theelectrode compartment such that an electrode slurry is drawn into theelectrode compartment. For example, the electrode slurry can bedelivered to a first end portion of the electrode compartment (e.g., theanode compartment 111 and/or the cathode compartment 121) by theinjection tool 140 using any of the methods described above and a vacuumcan be applied at a second end portion of the electrode compartment suchthat the vacuum applies a complimentary force. In some embodiments, avacuum assist technique can include recycling a drawn portion of theslurry back to the injection tool 140. In some embodiments, anelectrolyte can be added during and/or after the fill process (e.g., afill process including a vacuum assist) to substantially offset lossesof electrolyte through electrolyte evaporation. In some embodiments, theelectrode compartment can be evacuated and then with the vacuumdisconnected or turned off, the slurry can be drawn into the evacuatedcompartment.

In some embodiments, it can be desirable to fill the anode cell 111 andthe cathode cell 121 simultaneously and at a similar flow rate. In suchembodiments, the concurrent transfer of the anolyte to the anodecompartment and the catholyte to the cathode compartment can be suchthat the force on the separator and/or current collectors produced bythe introduction of the anolyte into the anode compartment balances theforce on the separator produced by the introduction of the catholyteinto the cathode compartment, thus minimizing deflection of theseparator 130. Said another way, when filling adjacent compartments thatare divided by a relatively thin, deformable member, I can be desirableto fill adjacent compartments such that deformation of the relativelythin member is minimized. In other embodiments, it can be desirable toonly fill an anode compartment or a cathode compartment.

Once loaded, the anode cell 111 and the cathode cell 121 can be sealed(as discussed in greater detail below) and the anode cell 111 and thecathode cell 121 can be operated in physical isolation, but electricalconnection (e.g., similarly to known configurations). This arrangementallows a battery (e.g., multiple battery cells 110 in electricalconnection) to adopt various form factors such that the battery can beconstructed into specialized shapes and sizes for particularapplications. The shape and design of the anode cell ill and the cathodecell 121 determines that of the resulting battery. The use of varyingelectrode material (e.g., semi-solid constituents, separators, and/orcavity volumes) determines the battery's power and energy capabilities.

In some embodiments, the anode and/or cathode particles have aneffective diameter of at least 1 μm. In some embodiments, the cathodeand/or anode particles have an effective diameter between approximately1 μm and approximately 10 μm. In other embodiments, the cathode and/oranode particles have an effective diameter of at least 10 μm or more.

In some embodiments, in order to increase the particle packing densityand therefore the energy density of the semi-solid suspension, whitestill maintaining a flowable semi-solid, the ion storage compoundparticles have a polydisperse size distribution in which the finestparticles present in at least 5 vol % of the total volume, is at least afactor of 5 smaller than the largest particles present in at least 5 vol% of the total volume. In some embodiments, in order to increase theparticle packing density and therefore the energy density of thesemi-solid suspension, while still maintaining a flowable semi-solid,the ion storage compound particles have a bidisperse size distribution(i.e., with two maxima in the distribution of particle number versusparticle size) in which the two maxima differ in size by at least afactor of 5.

In some embodiments, the size distribution of ion storage compoundparticles in the semi-solid is polydisperse, and the particle packingfraction is at least 50 vol %. In some embodiments, the particle packingfraction is between approximately 50 vol % and 70 vol %. In otherembodiments, the particle packing fraction is at least 70 vol % or more.

In some embodiments, the particles have morphology that is at leastequiaxed, and spherical, in order to increase the flowability anddecrease the viscosity of the semi-solid suspension while simultaneouslyachieving high particle packing density. In some embodiments, thespherical particles are dense, and in other embodiments the sphericalparticles are porous. In some embodiments, the spherical particles aremade by spray-drying a particle suspension to obtain sphericalagglomerates of smaller particles.

In some embodiments, the particles of ion storage material used in thesemi-solid suspension are sufficiently large that surface forces do notprohibit them from achieving high tap density while dry, and highpacking density when formulated into a semi-solid suspension. In someembodiments, the particle size is at least 1 μm. In other embodiments,the particle size is between approximately 1 μm and approximately 10 μm.In other embodiments, the particle size is at least 10 μm or more.

In some embodiments, high particle packing density is achievedsimultaneously with flowability and low viscosity by using dispersantsand surfactants well-known to those skilled in the arts of ceramicsprocessing and colloid chemistry. These additives may be, for example,organic molecules having a C₆ to C₁₂ backbone used to provide stericforces when adsorbed on the particles. Examples of such additivesinclude stearic acid, and the commercially available surfactantTriton-X-100.

In some embodiments, a redox mediator is used to improve charge transferwithin the semi-solid suspension. In some embodiments, the redoxmediator is based on Fe²⁺ or V²⁺, V³⁺, or V⁴⁺. In one embodiment, theredox mediator is ferrocene.

In some embodiments, dissolved redox ions can be used, as in aconventional aqueous or non-aqueous flow battery, but in suchembodiments, the anolyte and/or catholyte has an increased solubilityfor such ions by using an ionic liquid as the solvent. In someembodiments, the redox chemistry is Fe—Cr, vanadium redox, or azinc-halogen chemistry.

In some embodiments, the conductive particles have shapes, which mayinclude spheres, platelets, or rods to optimize solids packing fraction,increase the semi-solid's net electronic conductivity, and improverheological behavior of the semi-solids. Low aspect or substantiallyequiaxed particles tend to flow well, however, they tend to have a lowpacking density.

In some embodiments, the particles have a plurality of sizes so as toincrease packing fraction by placing smaller particles in theinterstices of the larger particles. In particular, the particle sizedistribution can be bimodal, in which the average particle size of thelarger particle mode is at least 5 times larger than the averageparticle size of the smaller particle mode. The mixture of large andsmall particles improves flow of the material during cell loading andincreases solid volume fraction and packing density in the loaded cell.

In some embodiments, the nature of suspension can be modified prior toand subsequent to injection of the semi-solid into theunfilled-battery-subassembly receptacles in order to facilitate flowduring loading and packing density in the loaded cell.

In some embodiments, the particle suspension is initially stabilized byrepulsive interparticle steric forces that arise from surfactantmolecules. After the particle suspension is injected into theunfilled-battery-subassembly receptacles, chemical or heat treatmentscan cause these surface molecules to collapse or evaporate and promotedensification. In some embodiments, the suspension's steric forces aremodified intermittently during injection.

For example, the particle suspension can be initially stabilized byrepulsive interparticle electrostatic double layer forces to decreaseviscosity. The repulsive force reduces interparticle attraction andreduces agglomeration. After the particle suspension is injected intothe unfilled-battery-subassembly receptacles, the surface of theparticles can be further modified to reduce interparticle repulsiveforces and thereby promote particle attraction and packing. For example,ionic solutions such as salt solutions can be added to the suspension toreduce the repulsive forces and promote aggregation and densification soas to produce increased solids fraction loading after injection. In someembodiments, salt is added intermittently during suspension injection toincrease density in incremental layers.

In some embodiments, the cell compartments are loaded with a particlesuspension that is stabilized by repulsive forces between particlesinduced by an electrostatic double layer or short-range steric forcesdue to added surfactants or dispersants. Following loading, the particlesuspension is aggregated and densified by increasing the saltconcentration of the suspension. In some embodiments, the salt that isadded is a salt of a working ion for the battery (e.g., a lithium saltfor a lithium ion battery) and upon being added, causes the liquid phaseto become an ion-conducting electrolyte. The liquid phase comprises asolvent that is then used as the solvent component of the electrolyte(e.g., for a lithium rechargeable battery, may be one or more alkylcarbonates, or one or more ionic liquids). Upon increasing the saltconcentration, the electrical double layer causing repulsion between theparticles is “collapsed,” and attractive interactions cause theparticles to floc, aggregate, consolidate, or otherwise densify. Thisallows the electrode of the battery to be formed from the suspensionwhile it has a low viscosity, for instance by pouring, injecting, orpumping into the chamber that forms a net-shaped electrode, and thenallows particles within the suspension to be consolidated for improvedelectrical conduction, higher packing density, and longer service life.

In some embodiments, the injectable and flowable semi-solid is caused tobecome non-flowable by “fixing.” In some embodiments, fixing isperformed by action of photo-polymerization. In some embodiments, fixingis performed by action of electromagnetic radiation with wavelengthsthat are transmitted by the unfilled-battery-subassembly. In somespecific embodiments, one or more additives are added to the flowablesemi-solid to facilitate the fixing of the flowable semi-solid.

In some embodiments, the injectable and flowable semi-solid is caused tobecome non-flowable by “plasticizing.” In some embodiments, therheological properties of the injectable and flowable semi-solid aremodified by addition of a thinner, a thickener, or a plasticizing agent.In some specific embodiments, these agents promote processability andhelp retain compositional uniformity of the semi-solid under flowingconditions and compartment filling operations. In some specificembodiments, one or more additives are added to the flowable semi-solidto adjust its flow properties to accommodate processing requirements.

Semi-Solid Composition

In some embodiments, the anolyte and catholyte semi-solids provide ameans to produce a substance that functions collectively as anion-storage/ion-source, electron conductor, and ionic conductor in asingle medium that acts as a working electrode.

Any anolyte and/or catholyte semi-solid ion-storing redox composition asdescribed herein can have, when taken in moles per liter (molarity), atleast 10M concentration of redox species. In some embodiments, anyanolyte and/or catholyte semi-solids ion-storing redox composition canhave at least 12M, at least 15M, or at least 20M. The electrochemicallyactive material can be an ion storage material or any other compound orion complex that is capable of undergoing Faradaic reaction in order tostore energy. The electroactive material can also be a multiphasematerial including the above-described redox-active solid mixed with anon-redox-active phase, including solid-liquid suspensions, orliquid-liquid multiphase mixtures, including micelles or emulsionshaving a liquid ion-storage material intimately mixed with a supportingliquid phase. Systems that utilize various working ions can includeaqueous systems in which or OH⁻ are the working ions, non-aqueoussystems in which Li⁺, Na⁺, or other alkali ions are the working ions,even alkaline earth working ions such as Ca²⁺ and Mg²⁺, or Al³⁺. In eachof these instances, a negative electrode storage material and a positiveelectrode storage material may be required, the negative electrodestoring the working ion of interest at a lower absolute electricalpotential than the positive electrode. The cell voltage can bedetermined approximately by the difference in ion-storage potentials ofthe two ion-storage electrode materials.

Systems employing both negative and positive ion-storage materials areparticularly advantageous because there are no additionalelectrochemical byproducts in the cell. Both the positive and negativeelectrodes materials are insoluble in the flow electrolyte and theelectrolyte does not become contaminated with electrochemicalcomposition products that must be removed and regenerated. In addition,systems employing both negative and positive lithium ion-storagematerials are particularly advantageous when using non-aqueouselectrochemical compositions.

In some embodiments, the semi-solid ion-storing redox compositionsinclude materials proven to work in conventional, solid lithium-ionbatteries. In some embodiments, the positive semi-solid electroactivematerial contains lithium positive electroactive materials and thelithium cations are shuttled between the negative electrode and positiveelectrode, intercalating into solid, host particles suspended in aliquid electrolyte.

In some embodiments at least one of the energy storage electrodesincludes a condensed ion-storing liquid of a redox-active compound,which may be organic or inorganic, and includes but is not limited tolithium metal, sodium metal, lithium-metal alloys, gallium and indiumalloys with or without dissolved lithium, molten transition metalchlorides, thionyl chloride, and the like, or redox polymers andorganics that are liquid under the operating conditions of the battery.Such a liquid form may also be diluted by or mixed with another,non-redox-active liquid that is a diluent or solvent, including mixingwith such diluents to form a lower-melting liquid phase. However, unlikea conventional flow cell catholyte or anolyte, the redox-activecomponent will comprise, by mass, at least 10% of the total mass of theflowable electrolyte. In other embodiments, the redox-active componentwill comprise, by mass, between approximately 10% and 25% of the totalmass of the flowable electrolyte. In other embodiments, the redox-activecomponent will comprise, by mass, at least 25% or more of the total massof the flowable electrolyte.

In some embodiments, the redox-active electrode material, whether usedas a semi-solid or a condensed liquid format as defined above, comprisesan organic redox compound that stores the working ion of interest at apotential useful for either the positive or negative electrode of abattery. Such organic redox-active storage materials include “p”-dopedconductive polymers such as polyaniline or polyacetylene basedmaterials, polynitroxide or organic radical electrodes (such as thosedescribed in: H. Nishide et al., Electrochim. Acta, 50, 827-831, (2004),and K. Nakahara, et al., Chem. Phys. Leu., 359, 351-354 (2002)),carbonyl based organics, and oxocarbons and carboxylate, includingcompounds such as Li₂C₆O₆, Li₂C₈H₄O₄, and Li₂C₆H₄O₄ (see for example M.Armand et al., Nature Materials, DOI: 10.1038/nmat2372) and organosulfurcompounds.

In some embodiments, organic redox compounds that are electronicallyinsulating are used. In some instance, the redox compounds are in acondensed liquid phase such as liquid or flowable polymers that areelectronically insulating. In such cases, the redox active slurry may ormay not contain an additional carrier liquid. Additives can be combinedwith the condensed phase liquid redox compound to increase electronicconductivity. In some embodiments, such electronically insulatingorganic redox compounds are rendered electrochemically active by mixingor blending with particulates of an electronically conductive material,such as solid inorganic conductive materials including but not limitedto metals, metal carbides, metal nitrides, metal oxides, and allotropesof carbon including carbon black, graphitic carbon, carbon fibers,carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenic carbonsincluding “buckyballs”, carbon nanotubes (CNTs), multiwall carbonnanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene sheetsor aggregates of graphene sheets, and materials comprising fullerenicfragments.

In some embodiments, such electronically insulating organic redoxcompounds are rendered electronically active by mixing or blending withan electronically conductive polymer, including but not limited topolyaniline or polyacetylene based conductive polymers orpoly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole, polythiophene,poly(p-phenylene), poly(triphenylene), polyazulene, polyfluorene,polynaphtalene, polyanthracene, polyfuran, polycarbazole,tetrathiafulvalene-substituted polystyrene, ferrocence-substitutedpolyethylene, carbazole-substituted polyethylene, polyoxyphenazine,polyacenes, or poly(heteroacenes. The conductive additives form anelectrically conducting framework within the insulating liquid redoxcompounds that significantly increases the electrically conductivity ofthe composition. In some embodiments, the conductive addition forms apercolative pathway to the current collector.

In some embodiments the redox-active electrode material comprises a solor gel, including for example metal oxide sols or gels produced by thehydrolysis of metal alkoxides, amongst other methods generally known as“sol-gel processing.” Vanadium oxide gels of composition V_(x)O_(y) areamongst such redox-active sol-gel materials.

Other suitable positive active materials include solid compounds knownto those skilled in the art as those used in NiMH (Nickel-Metal Hydride)Nickel Cadmium (NiCd) batteries. Still other positive electrodecompounds for Li storage include those used in carbon monofluoridebatteries, generally referred to as CFx, or metal fluoride compoundshaving approximate stoichiometry MF₂ or MF₃ where M comprises Fe, Bi,Ni, Co, Ti, V. Examples include those described in H. Li, P. Balaya, andJ. Maier, Li-Storage via Heterogeneous Reaction in Selected Binary MetalFluorides and Oxides, Journal of The Electrochemical Society, 151 [11]A1878-A1885 (2004), M. Bervas, A. N. Mansour, W.-S. Woon, J. F.Al-Sharab, F. Badway, F. Cosandey, L. C. Klein, and G. G. Amatucci,“Investigation of the Lithiation and Delithiation Conversion Mechanismsin a Bismuth Fluoride Nanocomposites”, J. Electrochem. Soc., 153, A799(2006), and I. Plitz, F. Badway, J. Al-Sharab, A. DuPasquier, F.Cosandey and G. G. Amatucci, “Structure and Electrochemistry ofCarbon-Metal Fluoride Nanocomposites Fabricated by a Solid State RedoxConversion Reaction”, J. Electrochem. Soc., 152, A307 (2005).

As another example, fullerenic carbon including single-wall carbonnanotubes (SWNTs), multiwall carbon nanotubes (MWNTs), or metal ormetalloid nanowires may be used as ion-storage materials. One example isthe silicon nanowires used as a high energy density storage material ina report by C. K. Chan, H. Peng, G. Liu, K. McIlwrath, X. F. Zhang, R.A. Huggins, and Y. Cui, High-performance lithium battery anodes usingsilicon nanowires, Nature Nanotechnology, published online 16 Dec. 2007;doi:10.1038/nnano.2007.411.

Exemplary electroactive materials for the positive electrode in alithium system include the general family of ordered rocksalt compoundsLiMO₂ including those having the α-NaFeO₂ (so-called “layeredcompounds”) or orthorhombic-LiMnO₂ structure type or their derivativesof different crystal symmetry, atomic ordering, or partial substitutionfor the metals or oxygen. M comprises at least one first-row transitionmetal but may include non-transition metals including but not limited toAl, Ca, Mg, or Zr. Examples of such compounds include LiCoO₂, LiCoO₂doped with Mg, LiNiO₂, Li(Ni, Co, Al)O₂ (known as “NCA”) and Li(Ni, Mn,Co)O₂ (known as “NMC”). Other families of exemplary electroactivematerials includes those of spinel structure, such as LiMn₂O₄ and itsderivatives, so-called “layered-spinel nanocomposites” in which thestructure includes nanoscopic regions having ordered rocksalt and spinelordering, olivines LiMPO₄ and their derivatives, in which M comprisesone or more of Mn, Fe, Co, or Ni, partially fluorinated compounds suchas LiVPO₄F, other “polyanion” compounds as described below, and vanadiumoxides V_(x)O_(y) including V₂O₅ and V₆O₁₁.

In one or more embodiments the active material comprises a transitionmetal polyanion compound, for example as described in U.S. Pat. No.7,338,734. In one or more embodiments the active material comprises analkali metal transition metal oxide or phosphate, and for example, thecompound has a composition A_(x)(M′_(1-a)M″_(a))_(y)(XD₄)_(z),A_(x)(M′_(1-a)M″_(a))_(y)(DXD₄)_(z), orA_(x)(M′_(1-a)M″_(a))_(y)(X₂D₇)_(z), and have values such that x, plusy(1-a) times a formal valence or valences of M′, plus ya times a formalvalence or valence of M″, is equal to z times a formal valence of theXD₄, X₂D₇, or DXD₄ group; or a compound comprising a composition(A_(1-a)M″_(a))_(x)M′_(y)(XD₄)_(z),(A_(1-z)M″_(a))_(x)M′_(y)(DXD₄)_(z)(A_(1-a)M″_(a))_(x)M′_(y)(X₂D₇), andhave values such that (1−a)x plus the quantity ax times the formalvalence or valences of M″ plus y times the formal valence or valences ofM′ is equal to z times the formal valence of the XD₄, X₂D₇ or DXD₄group. In the compound, A is at least one of an alkali metal andhydrogen, M′ is a first-row transition metal, X is at least one ofphosphorus, sulfur, arsenic, molybdenum, and tungsten, M″ any of a GroupIIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIBmetal, D is at least one of oxygen, nitrogen, carbon, or a halogen. Thepositive electroactive material can be an olivine structure compoundLiMPO₄, where M is one or more of V, Cr, Mn, Fe, Co, and Ni, in whichthe compound is optionally doped at the Li, M or O-sites. Deficienciesat the Li-site are compensated by the addition of a metal or metalloid,and deficiencies at the O-site are compensated by the addition of ahalogen. In some embodiments, the positive active material comprises athermally stable, transition-metal-doped lithium transition metalphosphate having the olivine structure and having the formula(Li_(1-x)Z_(x))MPO₄, where M is one or more of V, Cr, Mn, Fe, Co, andNi, and Z is a non-alkali metal dopant such as one or more of Ti, Zr,Nb, Al, or Mg, and x ranges from 0.005 to 0.05.

In other embodiments, the lithium transition metal phosphate materialhas an overall composition of Li_(1-x-z)M_(1+z)PO₄, where M comprises atleast one first row transition metal selected from the group consistingof Ti, V, Cr, Mn, Fe, Co and Ni, where x is from 0 to 1 and z can bepositive or negative. M includes Fe, z is between about 0.15 and −0.15.The material can exhibit a solid solution over a composition range of0<x<0.15, or the material can exhibit a stable solid solution over acomposition range of x between 0 and at least about 0.05, or thematerial can exhibit a stable solid solution over a composition range ofx between 0 and at least about 0.07 at room temperature (22-25° C.). Thematerial may also exhibit a solid solution in the lithium-poor regime,e.g., where x≧0.8, or x≧0.9, or x≧0.95.

In some embodiments the redox-active electrode material comprises ametal salt that stores an alkali ion by undergoing a displacement orconversion reaction. Examples of such compounds include metal oxidessuch as CoO, Co₃O₄, NiO, CuO, MnO, typically used as a negativeelectrode in a lithium battery, which upon reaction with Li undergo adisplacement or conversion reaction to form a mixture of Li₂O and themetal constituent in the firm of a more reduced oxide or the metallicform. Other examples include metal fluorides such as CuF₂, FeF₂, FeF₃,BiF₃, CoF₂, and NiF₂, which undergo a displacement or conversionreaction to form LiF and the reduced metal constituent. Such fluoridesmay be used as the positive electrode in a lithium battery. In otherembodiments the redox-active electrode material comprises carbonmonofluoride or its derivatives. In some embodiments the materialundergoing displacement or conversion reaction is in the form ofparticulates having on average dimensions of 100 nanometers or less. Insome embodiments the material undergoing displacement or conversionreaction comprises a nanocomposite of the active material mixed with aninactive host, including but not limited to conductive and relativelyductile compounds such as carbon, or a metal, or a metal sulfide. FeS₂and FeF₃ can also be used as cheap and electronically conductive activematerials in a nonaqueous or aqueous lithium system.

In some embodiments, the working ion is selected from the groupconsisting of Li⁺, Na⁺, H⁺, Mg²⁺, Al³⁺, or Ca²⁺.

In some embodiments, the working ion is selected from the groupconsisting of Li⁺ or Na⁺.

In some embodiments, the flowable semi-solid ion-storing redoxcomposition includes a solid including an ion storage compound.

In some embodiments, the ion is proton or hydroxyl ion and the ionstorage compound includes those used in a nickel-cadmium or nickel metalhydride battery.

In some embodiments, the ion is lithium and the ion storage compound isselected from the group consisting of metal fluorides such as CuF₂,FeF₂, FeF₃, BiF₃, CoF₂, and NiF₂.

In some embodiments, the ion is lithium and the ion storage compound isselected from the group consisting of metal oxides such as CoO, Co₃O₄,NiO, CuO, MnO.

In some embodiments, the ion is lithium and the ion storage compoundincludes an intercalation compound selected from compounds with formulaLi_(1-x-z)M_(1-z)PO₄, wherein M includes at least one first rowtransition metal selected from the group consisting of Ti, V, Cr, Mn,Fe, Co and Ni, wherein x is from 0 to 1 and z can be positive ornegative.

In some embodiments, the ion is lithium and the ion storage compoundincludes an intercalation compound selected from compounds with formula(Li_(1-x)Z_(x))MPO₄, where M is one or more of V, Cr, Mn, Fe, Co, andNi, and Z is a non-alkali metal dopant such as one or more of Ti, Zr,Nb, Al, or Mg, and x ranges from 0.005 to 0.05.

In some embodiments, the ion is lithium and the ion storage compoundincludes an intercalation compound selected from compounds with formulaLiMPO₄, where M is one or more of V, Cr, Mn, Fe, Co, and Ni, in whichthe compound is optionally doped at the Li, M or O-sites.

In some embodiments, the ion is lithium and the ion storage compoundincludes an intercalation compound selected from the group consisting ofA_(x)(M′_(1-a)M″_(a))_(y)(XD₄)_(z), A_(x)(M′_(1-a)M″_(a))_(y)(DXD₄)_(z),and A_(x)(M′_(1-a)M″_(a))_(y)(X₂D⁷)_(z), wherein x, plus y(1-a) times aformal valence or valences of M′, plus ya times a formal valence orvalence of M″, is equal to z times a formal valence of the XD₄, X₂D₇, orDXD₄ group; and A is at least one of an alkali metal and hydrogen, M′ isa first-row transition metal, X is at least one of phosphorus, sulfur,arsenic, molybdenum, and tungsten, M″ any of a Group IIA, IIIA, IVA, VA,VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIB metal, D is at leastone of oxygen, nitrogen, carbon, or a halogen.

In some embodiments, the ion is lithium and the ion storage compoundincludes an intercalation compound selected from the group consisting ofA_(1-a)M″_(a))_(x)M′_(y)(XD₄), (A_(1-a)M″_(a))_(x)M′_(y)(DXD₄)z andA_(1-a)M″_(a))_(x)M′_(y)(X₂D₇)_(z), where (1-a)x plus the quantity axtimes the formal valence or valences of M″ plus y times the formalvalence or valences of M′ is equal to z times the formal valence of theXD₄, X₂D₇ or DXD₄ group, and A is at least one of an alkali metal andhydrogen, M′ is a first-row transition metal, X is at least one ofphosphorus, sulfur, arsenic, molybdenum, and tungsten, M″ any of a GroupIIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIBmetal, D is at least one of oxygen, nitrogen, carbon, or a halogen.

In some embodiments, the ion is lithium and the ion storage compoundincludes an intercalation compound selected from the group consisting ofordered rocksalt compounds LiMO₂ including those having the α-NaFeO₂ andorthorhombic-LiMnO₂ structure type or their derivatives of differentcrystal symmetry, atomic ordering, or partial substitution for themetals or oxygen, where M includes at least one first-row transitionmetal but may include non-transition metals including but not limited toAl, Ca, Mg, or Zr.

In some embodiments, the flowable semi-solid ion-storing redoxcomposition includes a solid including amorphous carbon, disorderedcarbon, graphitic carbon, or a metal-coated or metal-decorated carbon.

In some embodiments, the flowable semi-solid ion-storing redoxcomposition includes a solid including a metal or metal alloy ormetalloid or metalloid alloy or silicon.

In some embodiments, the flowable semi-solid ion-storing redoxcomposition includes a solid including nanostructures includingnanowires, nanorods, and nanotetrapods.

In some embodiments, the flowable semi-solid ion-storing redoxcomposition includes a solid including an organic redox compound.

In some embodiments, the positive electrode includes a flowablesemi-solid ion-storing redox composition including a solid selected fromthe group consisting of ordered rocksalt compounds LiMO₂ including thosehaving the α-NaFeO₂ and orthorhombic-LiMnO₂ structure type or theirderivatives of different crystal symmetry, atomic ordering, or partialsubstitution for the metals or oxygen, wherein M includes at least onefirst-row transition metal but may include non-transition metalsincluding but not limited to Al, Ca, Mg, or Zr and the negativeelectrode includes a flowable semi-solid ion-storing redox compositionincluding a solid selected from the group consisting of amorphouscarbon, disordered carbon, graphitic carbon, or a metal-coated ormetal-decorated carbon.

In some embodiments, the positive electrode includes a flowablesemi-solid ion-storing redox composition including a solid selected fromthe group consisting of A_(x)(M′_(1-a)M″_(a))_(y)(XD₄)_(z),A_(x)(M′_(1-a)M″_(a))_(y)(DXD₄)_(z), andA_(x)(M′_(1-a)M″_(a))_(y)(X₂D₇)_(z), and where x, plus y(1-a) times aformal valence or valences of M′, plus ya times a formal valence orvalence of M″, is equal to z times a formal valence of the XD₄, X₂D₇, orDXD₄ group, and A is at least one of an alkali metal and hydrogen, M′ isa first-row transition metal, X is at least one of phosphorus, sulfur,arsenic, molybdenum, and tungsten, M″ any of a Group IIA, IIIA, IVA, VA,VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIB metal, D is at leastone of oxygen, nitrogen, carbon, or a halogen and the negative electrodeincludes a flowable semi-solid ion-storing redox composition including asolid selected from the group consisting of amorphous carbon, disorderedcarbon, graphitic carbon, or a metal-coated or metal-decorated carbon.

In some embodiments, the positive electrode includes a flowablesemi-solid ion-storing redox composition including a compound with aspinel structure.

In some embodiments, the positive electrode includes a flowablesemi-solid ion-storing redox composition including a compound selectedfrom the group consisting of LiMn₂O₄ and its derivatives; layered-spinelnanocomposites in which the structure includes nanoscopic regions havingordered rocksalt and spinel ordering; so-called “high voltage spinels”with a potential vs. Li/Li+ that exceeds 4.3V including but not limitedto LiNi0.5Mn1.5O4; olivines LiMPO₄ and their derivatives, in which Mincludes one or more of Mn, Fe, Co, or Ni, partially fluorinatedcompounds such as LiVPO₄F, other “polyanion” compounds, and vanadiumoxides V_(x)O_(y) including V₂O₅ and V₆O₁₁.

In some embodiments the semi-solid flow battery is a lithium battery,and the negative electrode active compound comprises graphite, graphiticboron-carbon alloys, hard or disordered carbon, lithium titanate spinel,or a solid metal or metal alloy or metalloid or metalloid alloy thatreacts with lithium to form intermetallic compounds, including themetals Sn, Bi, Zn, Ag, and Al, and the metalloids Si and Ge.

Exemplary electroactive materials for the negative electrode in the caseof a lithium working ion include graphitic or non-graphitic carbon,amorphous carbon, or mesocarbon microbeads; an unlithiated metal ormetal alloy, such as metals including one or more of Ag, Al, Au, B, Ga,Ge, In, Sb, Sn, Si, or Zn, or a lithiated metal or metal alloy includingsuch compounds as LiAl, Li₉Al₄, Li₃Al, LiZn, LiAg, Li₁₀Ag₃, Li₅B₄,Li₇B₆, Li₁₂Si₇, Li₂₁Si₈, Li₁₃Si₄, Li₂₁Si₅, Li₅Sn₂, Li₁Sn₅, Li₇Sn₂,Li₂₂Sn₅, Li₂Sb, Li₃Sb, LiBi, or Li₃Bi, or amorphous metal alloys oflithiated or non-lithiated compositions.

In some embodiments, the negative electrode includes a semi-solidion-storing redox composition including graphite, graphitic boron-carbonalloys, hard or disordered carbon, lithium titanate spinel, or a solidmetal or metal alloy or metalloid or metalloid alloy that reacts withlithium to form intermetallic compounds, including the metals Sn, Bi,Zn, Ag, and Al, and the metalloids Si and Ge.

The current collector is electronically conductive and should beelectrochemically inactive under the operation conditions of the cell.Typical current collectors for lithium cells include copper, aluminum,or titanium for the negative current collector and aluminum for thepositive current collector, in the form of sheets or mesh, or anyconfiguration for which the current collector may be distributed in theelectrolyte and permit fluid flow. Selection of current collectormaterials is well-known to those skilled in the art. In someembodiments, aluminum is used as the current collector for positiveelectrode. In some embodiments, copper is used as the current collectorfor negative electrode. In other embodiments, aluminum is used as thecurrent collector for negative electrode.

In some embodiments, the negative electrode can be a conventionalstationary electrode, while the positive electrode includes a semi-solidredox composition. In other embodiments, the positive electrode can be aconventional stationary electrode, while the negative electrode includesa semi-solid redox composition.

Current collector materials can be selected to be stable at theoperating potentials of the positive and negative electrodes of the flowbattery. In non-aqueous lithium systems the positive current collectormay comprise aluminum, or aluminum coated with conductive material thatdoes not electrochemically dissolve at operating potentials of 2.5-5Vwith respect to Li/Li⁺. Such materials include Pt, Au, Ni, conductivemetal oxides such as vanadium oxide, and carbon. The negative currentcollector may comprise copper or other metals that do not form alloys orintermetallic compounds with lithium, carbon, and coatings comprisingsuch materials on another conductor.

In some embodiments, the electrochemical function of the semi-solidsredox cell is improved by mixing or blending the anode or cathodeparticles with particulates of an electronically conductive material,such as solid inorganic conductive materials including but not limitedto metals, metal carbides, metal nitrides, metal oxides, and allotropesof carbon including carbon black, graphitic carbon, carbon fibers,carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenic carbonsincluding “buckyballs”, carbon nanotubes (CNTs), multiwall carbonnanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene sheetsor aggregates of graphene sheets, and materials comprising fullerenicfragments. In some embodiments, such electronically insulating organicredox compounds are rendered electronically active by mixing or blendingwith an electronically conductive polymer, including but not limited topolyaniline or polyacetylene based conductive polymers orpoly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole, polythiophene,poly(p-phenylene), poly(triphenylene), polyazulene, polyfluorene,polynaphtalene, polyanthracene, polyfuran, polycarbazole,tetrathiafulvalene-substituted polystyrene, ferrocence-substitutedpolyethylene, carbazole-substituted polyethylene, polyoxyphenazine,polyacenes, or poly(heteroacenes).). In some embodiments, the resultingcatholyte or anolyte mixture has an electronic conductivity of at leastabout 10⁻⁶ S/cm. In other embodiments, the mixture has an electronicconductivity between approximately 10⁻⁶ S/cm and 10⁻³ S/cm. In otherembodiments, the mixture has an electronic conductivity of at leastabout 10⁻⁵ S/cm, or at least about 10⁻⁴ S/cm, of at least about 10⁻³S/cm or more.

In some embodiments, the anodic or cathodic particles can be caused tohave a partial or full conductive coating.

In some embodiments, the semi-solid ion-storing redox compositionincludes an ion-storing solid coated with a conductive coating material.In certain specific embodiments, the conductive coating material hashigher electron conductivity than the solid. In certain specificembodiments, the solid is graphite and the conductive coating materialis a metal, metal carbide, metal oxide, metal nitride, or carbon. Incertain specific embodiments, the metal is copper.

In some embodiments, the solid of the semi-solid ion-storing material iscoated with metal that is redox-inert at the operating conditions of theredox energy storage device. In some embodiments, the solid of thesemi-solid ion-storing material is coated with copper to increase theconductivity of the storage material particle, to increase the netconductivity of the semi-solid, and/or to facilitate charge transferbetween energy storage particles and conductive additives. In someembodiments, the storage material particle is coated with, about 1.5% byweight, metallic copper. In some embodiments, the storage materialparticle is coated with, about 3.0% by weight, metallic copper. In someembodiments, the storage material particle is coated with, about 8.5% byweight, metallic copper. In some embodiments, the storage materialparticle is coated with, about 10.0% by weight, metallic copper. In someembodiments, the storage material particle is coated with, about 15.0%by weight, metallic copper. In some embodiments, the storage materialparticle is coated with, about 20.0% by weight, metallic copper.

In some embodiments, the conductive coating is placed on the anodic orcathodic particles by chemical precipitation of the conductive elementand subsequent drying and/or calcination.

In some embodiments, the conductive coating is placed on the anodic orcathodic particles by electroplating (e.g., within a fluidized bed).

In some embodiments, the conductive coating is placed on the anodic orcathodic particles by co-sintering with a conductive compound andsubsequent comminution.

In some embodiments, the electrochemically active particles have acontinuous intraparticle conductive material or are embedded in aconductive matrix.

In some embodiments, a conductive coating and intraparticulateconductive network is produced by multicomponent-spray-drying asemi-solid of anode/cathode particles and conductive materialparticulates.

In some embodiments, conductive polymers are among the componentssemi-solid and provide an electronically conductive element. In someembodiments, the conductive polymers are one or more of: polyacetylene,polyaniline, polythiophene, polypyrrole, poly(p-phenylene),poly(triphenylene), polyazulene, polyfluorene, polynaphtalene,polyanthracene, polyfuran, polycarbazole, polyacenes,poly(heteroacenes). In some embodiments, the conductive polymer is acompound that reacts in-situ to form a conductive polymer on the surfaceof active materials particles. In one embodiment, the compound is2-hexylthiophene or 3-hexylthiophene and oxidizes during charging of thebattery to form a conductive polymer coating on solid particles in thecathode semi-solid suspension. In other embodiments, redox activematerial can be embedded in conductive matrix. The redox active materialcan coat the exterior and interior interfaces in a flocculated oragglomerated particulate of conductive material. In other embodiments,the redox-active material and the conductive material can be twocomponents of a composite particulate. Without being bound by any theoryor mode of operation, such coatings can pacify the redox activeparticles and can help prevent undesirable reactions with carrier liquidor electrolyte. As such, it can serve as a synthetic solid-electrolyteinterphase (SEI) layer.

In some embodiments, inexpensive iron compounds such as pyrite (FeS₂)are used as inherently electronically conductive ion storage compounds.In one embodiment, the ion that is stored is Li+.

In some embodiments, redox mediators are added to the semi-solid toimprove the rate of charge transfer within the semi-solid electrode. Insome embodiments, this redox mediator is ferrocene or aferrocene-containing polymer. In some embodiments, the redox mediator isone or more of tetrathiafulvalene-substituted polystyrene,ferrocene-substituted polyethylene, carbazole-substituted polyethylene.

In some embodiments, the surface conductivity or charge-transferresistance of current collectors used in the semi-solid battery isincreased by coating the current collector surface with a conductivematerial. Such layers can also serve as a synthetic SEI layer.Non-limiting examples of conductive-coating material include carbon, ametal, metal carbide, metal nitride, metal oxide, or conductive polymer.In some embodiments, the conductive polymer includes but is not limitedto polyaniline or polyacetylene based conductive polymers orpoly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole, polythiophene,poly(p-phenylene), poly(triphenylene), polyazulene, polyfluorene,polynaphtalene, polyanthracene, polyfuran, polycarbazole,tetrathiafulvalene-substituted polystyrene, ferrocence-substitutedpolyethylene, carbazole-substituted polyethylene, polyoxyphenazine,polyacenes, or poly(heteroacenes). In some embodiments, the conductivepolymer is a compound that reacts in-situ to form a conductive polymeron the surface of the current collector. In one embodiment, the compoundis 2-hexylthiophene and oxidizes at a high potential to form aconductive polymer coating on the current collector. In someembodiments, the current collector is coated with metal that isredox-inert at the operating conditions of the redox energy storagedevice.

The semi-solid redox compositions can include various additives toimprove the performance of the redox cell. The liquid phase of thesemi-solids in such instances would comprise a solvent, in which isdissolved an electrolyte salt, and binders, thickeners, or otheradditives added to improve stability, reduce gas formation, improve SEIformation on the negative electrode particles, and the like. Examples ofsuch additives include vinylene carbonate (VC), vinylethylene carbonate(VEC), fluoroethylene carbonate (FEC), or alkyl cinnamates, to provide astable passivation layer on the anode or thin passivation layer on theoxide cathode; propane sultone (PS), propene sultone (PrS), or ethylenethiocarbonate as antigassing agents; biphenyl (BP), cyclohexylbenzene,or partially hydrogenated terphenyls, as gassing/safety/cathodepolymerization agents; or lithium bis(oxatlato)borate as an anodepassivation agent.

In some embodiments, the non-aqueous positive and negative electrodesemi-solids redox compositions are prevented from absorbing impuritywater and generating acid (such as HF in the case of LiPF₆ salt) byincorporating compounds that getter water into the active materialsuspension or into the storage tanks or other plumbing of the system.Optionally, the additives are basic oxides that neutralize the acid.Such compounds include but are not limited to silica gel, calciumsulfate (for example, the product known as Drierite), aluminum oxide andaluminum hydroxide.

Example 1 Semi-Solid Filled Cell Using Lithium Metal Oxides forElectrode Materials Preparation of a Non-Aqueous Lithium Titanate SpinelAnode Semi-Solid:

A suspension containing 8% by volume of lithium titanium oxide(Li₄TisO₁₂) and 8% by volume carbon black as the conductive additive in84% by volume of a non-aqueous electrolyte consisting of LiPF₆ in amixture of alkyl carbonates was prepared by first mixing 0.7 g Li₄Ti₅O₁₂and 0.44 g of carbon black in the dry state using a TURBULA shaker-mixerfor 1 hr. 2.5 ml of the electrolyte was then added and the mixture wassonicated for 1 hr.

Preparation of a Non-Aqueous Lithium Cobalt Oxide Cathode Semi-Solid:

Suspensions containing 12% by volume of lithium cobalt oxide (LiCoO₂),8% by volume of carbon black, and the balance being an electrolyteconsisting of LiPF₆ in a mixture of alkyl carbonates, were prepared.1.05 g of lithium cobalt oxide was mixed with 0.22 g of the carbon usinga turbula mixture for 1 hr. Afterwards, the electrolyte was added in theappropriate amount to make up the balance of the semi-solid suspension,and mixture was sonicated for 1 hr.

Some embodiments described herein relate to a semi-solid suspension withgreater than about 45% active material by volume. Additionally, in someembodiments, a sufficient quantity of a conductive additive (e.g.,carbon black) can be added to the slurry to improve electricalconductivity and electrochemical performance of the electrode.Furthermore, some embodiments described herein relate to a repeatable,scalable, manufacturing-oriented formulation process.

In some embodiments, an electrochemically active semi-solid suspensioncan include about 20% to about 75% by volume of a cathode or anode ionstorage component, about 0.5% to about 25% by volume of a conductiveadditive component, and about 25% to about 70% by volume of anelectrolyte.

In some embodiments, slurry components can be mixed in a batch process(e.g., with a batch mixer), with a specific spatial and/or temporalordering of component addition, as described in more detail herein. Insome embodiments, slurry components can be mixed in a continuous process(e.g. in an extruder), with a specific spatial and/or temporal orderingof component addition.

In some embodiments, process conditions (temperature; shear rate or rateschedule; component addition sequencing, location, and rate; mixing orresidence time) can be selected and/or modified to control theelectrical, rheological, and/or compositional (e.g., uniformity)properties of the prepared slurry. In some embodiments, the mixingelement (e.g., roller blade edge) velocity is between about 0.5 cm/s andabout 50 cm/s. In some embodiments, the minimum gap between which fluidis being flowed in the mixing event (e.g. distance from roller bladeedge to mixer containment wall) is between about 0.05 mm and about 5 mm.Therefore, the shear rate (velocity scale divided by length scale) isaccordingly between about 1 and about 10,000 inverse seconds. In someembodiments, the shear rate can be less than 1 inverse second, and inother embodiments, the shear rate is greater than 10,000 inverseseconds.

For example, the process conditions can be selected to produce aprepared slurry having a mixing index of at least about 0.80, at leastabout 0.90, at least about 0.95, or at least about 0.975. In someembodiments, the process conditions can be selected to produce aprepared slurry having an electronic conductivity of at least about 10⁻⁶S/cm, at least about 10⁻⁵ S/cm, at least about 10⁻⁴ S/cm, at least about10⁻³ S/cm, or at least about 10⁻² S/cm. In some embodiments, the processconditions can be selected to produce a prepared slurry having anapparent viscosity at room temperature of less than about 100,000 Pa-s,less than about 10,000 Pa-s, or less than about 1,000 Pa-s, all at anapparent sheer rate of 1,000 s⁻¹. In some embodiments, the processconditions can be selected to produce a prepared slurry having two ormore properties as described herein.

The mixing and forming of a slurry electrode generally includes: (i) rawmaterial conveyance and/or feeding, (ii) mixing, (iii) mixed slurryconveyance, (iv) dispensing and/or extruding, and (v) forming. In someembodiments, multiple steps in the process can be performed at the sametime and/or with the same piece of equipment. For example, the mixingand conveyance of the slurry can be performed at the same time with anextruder. Each step in the process can include one or more possibleembodiments. For example, each step in the process can be performedmanually or by any of a variety of process equipment. Each step can alsoinclude one or more sub-processes and, optionally, an inspection step tomonitor process quality.

Raw material conveyance and/or feeding can include: batch based manualweighing of material with natural feeding (e.g., allowing the mixer toaccept material into the mixture without external force), batch basedmanual weighing of material with forced feeding either by a pistonmechanism or a screw-based “side stuffer,” gravimetric screw solidsfeeders with natural feeding (e.g., feed at the rate which the mixer cannaturally accept material), gravimetric screw solids feeders with forcedfeeding (e.g., units sold by Brabender Industries Inc combined with apiston mechanism or a screw-based ‘side stuffer’), and/or any othersuitable conveyance and/or feeding methods and/or any suitablecombination thereof.

In some embodiments, the slurry can be mixed using a Banburry® stylebatch mixer, a mixing section of a twin screw extruder, a centrifugalplanetary mixer, and/or a planetary mixer. In some embodiments, theslurry can be sampled and/or monitored after mixing to measure and/orevaluate homogeneity, rheology, conductivity, viscosity, and/or density.

In some embodiments, for example after mixing, the slurry can beconveyed and/or pressurized, for example using a piston pump,peristaltic pump, gear/lobe pump, progressing cavity pump, single screwextruder, conveying section of a twin screw extruder, and/or any othersuitable conveying device. In some embodiments, the torque and/or powerof the conveying device, the pressure at the conveying device exit, theflow rate, and/or the temperature can be measured, monitored and/orcontrolled during the conveying and/or pressurizing.

In some embodiments, for example after conveying and/or pressurizing,the slurry can be dispensed and/or extruded. The slurry can be dispensedand/or extruded using, for example, a “hanger die” sheet extrusion die,a “winter manifold” sheet extrusion die, a profile-style sheet extrusiondie, an arbitrary nozzle operable to apply a continuous stream ofmaterial to a substrate, injection into a mold of the correct size andshape (e.g., filling a pocket with material), and/or any other suitabledispensing device.

In some embodiments, after dispensing the slurry can be formed into afinal electrode. For example, the slurry can be calendar roll formed,stamped and/or pressed, subjected to vibrational settling, and/or cut indiscrete sections. Additionally, in some embodiments, unwanted portionsof material can be removed (e.g., masking and cleaning) and optionallyrecycled back into the slurry manufacturing process.

The systems, mixing equipment, processes and methods described hereincan be used to produce a semi-solid suspension (e.g., slurry) suitablefor use in electrochemical devices (e.g., batteries). The semi-solidsuspension produced by such systems and methods are suitable for theformulation of a slurry-based electrodes with particular properties, forexample, rheology, conductivity, and electrochemical performance. Forexample, some suitable mixing devices include batch mixers (e.g., C. W.Brabender or Banburry® style), continuous compounding devices such asported single or twin screw extruders (e.g., Leistritz, Haake), highshear mixers such as blade-style blenders, high speed kneading machines,and/or rotary impellers. In some embodiments, the mixing device can beoperable to control the flowability of the slurry by regulating thetemperature, and/or to control the slurry homogeneity by modulating thechemical composition.

In embodiments in which a batch mixer is used to mix the slurry, theslurry can be transferred from the batch mixer to another piece ofprocessing equipment, e.g., an extruder. In such embodiments, thetransfer method can be chosen so as to minimize electrolyte losses, tonot appreciably disrupt the slurry state, and/or to not introduce otherprocessing difficulties, such as entrainment of ambient gases. Inembodiments in which an extruder (e.g., twin screw) is used to mix theslurry, mixing and material conveyance occur together, thus eliminatinga process step.

In some embodiments, some electrolyte loss can be tolerated and used asa control specification, and the amount that can be tolerated generallydecreases as electrolyte volume fraction increases and/or mixing indexincreases. For example, at a mixing index of 0.8, the maximumelectrolyte loss can be controlled to less than about 39%, to less thanabout 33%, or to less than about 27%. At a mixing index of 0.9, themaximum electrolyte loss can be controlled to less than about 5%, toless than about 4%, or to less than about 3%. At mixing indices higherthan 0.9, the maximum electrolyte loss can be controlled to less thanabout 5%, to less than about 4%, or to less than about 3%. Componentconcentrations can be calculated to determine and/or predict tolerablelosses, and vary according to the specific components. In otherembodiments, loss tolerances will be higher while in others they will bemore restrictive.

In some embodiments, the composition of the slurry and the mixingprocess can be selected to homogeneously disperse the components of theslurry, achieve a percolating conductive network throughout the slurryand sufficiently high bulk electrical conductivity, which correlates todesirable electrochemical performance as described in further detailherein, to obtain a rheological state conducive to processing, which mayinclude transfer, conveyance (e.g., extrusion), dispensing, segmentingor cutting, and post-dispense forming (e.g., press forming, rolling,calendering, etc.), or any combination thereof.

The systems and methods described below are examples of cell and modulefabrication. While specific embodiments are discussed, it should beunderstood that more than one embodiment can be integrated to compose,for example, a hybrid embodiment. The systems and methods describedbelow can be applied to half cells (e.g., an anode cell or a cathodecell), full cells (e.g., and anode cell and a cathode cell separated byan ion permeable membrane), or modules (e.g., multiple full cells). Anyof the semi-solids (or portions thereof) described above can be used inany of the embodiments described below. Similarly, any of the methods ofmixing described above can be used in conjunction with any of theembodiments described below.

FIGS. 2-4 show a system 200 illustrating a method of manufacturing anelectrochemical cell, according to an embodiment. The system 200includes a battery cell 210 and an injection tool 240. The battery cell210 includes an anode cell 211, a cathode cell 221, and a separator 230disposed therebetween. The anode cell 211 includes current collector213, a frame 214, and a port 212, and defines a cavity 215. The frame214 can be configured to provide structural support to the anode cell211. The current collector 213 can be any of those described above.Therefore, the current collector 213 is not described in further detailherein. The cavity 215 is defined by the current collector 213, theframe 214, and the separator 230 (see e.g., FIG. 4). The port 212 is, atleast temporarily (e.g., during manufacturing) in fluid communicationwith the cavity 215 such that the cavity 215 can receive a flow of anelectrode slurry, as further described herein. The cathode cell 221includes a current collector 223, a frame 224, and a port 222, anddefines a cavity 215. The cathode cell 221 can be substantially similarin form to the anode cell 211. Therefore, the components of the cathodecell 221 are not described in further detail herein.

The injection tool 240 includes a manifold 241 having an anode portion242 and a cathode portion 243. The anode portion 242 is physically andfluidically coupled to a set of anode injection nozzles 244 (see e.g.,FIG. 3). Similarly, the cathode portion 243 is physically andfluidically coupled to a set of cathode injection nozzles 245 (see e.g.,FIG. 3). The manifold 241 can be any suitable shape, size, orconfiguration and is configured to selectively transfer a flow ofelectrode material to the battery cell 210. In some embodiments, themanifold 241 can be at least operably coupled to any other suitablemachinery (not shown) included in the system 200. For example, themanifold 241 can be operably coupled to a motor, a feeder, and injectortool (e.g., a syringe device), or the like. In this manner, the manifold241 can receive a flow of an electrode material. More specifically, thesystem 200 can be configured to deliver an anode flowable semi-solid tothe anode portion 242 of the manifold 241 and a cathode flowablesemi-solid to the cathode portion 243.

At least a portion of the anode injection nozzles 244 and at least aportion of the cathode injection nozzles 245 can be movably disposedwithin the anode cavity 215 and the cathode cavity 225, respectively. Asshown in FIG. 3, the anode injection nozzles 244 and the cathodeinjection nozzles 245 can be any number of relatively small tubesconfigured to be coupled together such that the overall shape of theinjection nozzles 244 and 245 substantially correspond to a geometry ofthe anode cavity 215 and the cathode cavity 225, respectively. Forexample, in some embodiments, the anode injection nozzles 244 and thecathode injection nozzles 245 can be any number of tubes (e.g., needles)brazed together and machined into a desired form (e.g., corresponding tothe anode cavity 215 and the cathode cavity 225, respectively). Whileshown in FIG. 3 as being formed from multiple tubes or conduits, in someembodiments, an anode injection nozzle 244 and/or a cathode injectionnozzle 245 can be a monolithically formed structure defining, forexample, a slotted channel.

FIG. 5 is a flowchart illustrating a method 260 of manufacturing anelectrochemical cell (e.g., the battery cell 210) utilizing the system200. The method 260 includes disposing an injection nozzle in anelectrode compartment, at 261. For example, in use with the system 200,the anode injection nozzle 244 and the cathode injection nozzle 245 canbe disposed within the anode cavity 215 and the cathode cavity 225,respectively. More specifically, an end portion of the anode injectionnozzle 244 can be disposed adjacent to an end portion of the anodecavity 215 (e.g., an end opposite the port 212) and an end portion ofthe cathode injection nozzle 245 can be disposed adjacent to an endportion of the cathode cavity (e.g., an end opposite the port 222).

The method 260 includes transferring a semi-solid suspension electrodematerial to the electrode compartment through the injection nozzle, at262. For example, in the system 200, the anode portion 242 of themanifold 241 can receive a flow of an anode slurry (any of thosedescribed above) and the cathode portion 243 of the manifold 242 canreceive a flow of a cathode slurry (any of those described above). Theanode slurry and the cathode slurry can be delivered to the manifold 241in any suitable manner. For example, in some embodiments, the anodeslurry and the cathode slurry can be delivered from an anode reservoirand a cathode reservoir, respectively, to the manifold 241 via anapplied pressure (e.g., mechanically applied force, user applied force,gravitational force, centrifugal force, or the like). In this manner,the anode slurry and the cathode slurry are placed under pressure suchthat the anode slurry and cathode slurry flow within the anode injectionnozzle 244 and the cathode injection nozzle 245, respectively.Therefore, the anode injection nozzle 244 can deliver a flow of theanode slurry to the anode cavity 215 and the cathode injection nozzle245 can deliver a flow of the cathode slurry to the cathode cavity 225.

The method 260 includes withdrawing the injection nozzle from theelectrode compartment during at least a portion of the transferring, at263. For example, during injection of the slurry, the anode injectionnozzle 244 and the cathode injection nozzle 245 are configured to movewithin the anode cavity 215 and the cathode cavity 225, respectively, inthe direction of the ports 212 and 222 (e.g., the nozzles are withdrawnfrom the cavities). In some embodiments, the injection nozzles 244 and245 can be heated and/or vibrated (e.g., in a peristaltic motion) tofacilitate the flow of the anode slurry and cathode slurry. In someembodiments, such as those including multiple tubes that are coupled toform the injection nozzles, various tubes can be configured to transfervarious portions of the slurry (e.g., a given tube can transfer asealant while a different tube can transfer a surfactant).

As the slurries are transferred to the anode cavity 215 and the cathodecavity 225, the pressure within the anode cavity 215 is configured to bein equilibrium with the pressure within the cathode cavity 225.Similarly stated, the anode slurry can be transferred to the anodecavity at a flow rate that is substantially equal to the flow rate ofthe cathode slurry being transferred to the cathode cavity such that thepressures within the anode cavity 215 and the cathode cavity 225 aresubstantially equal. In other embodiments, the flow rates of the anodeslurry and the cathode slurry can substantially correspond to thedensity of the slurry. Thus, the pressures within the anode cavity 215and the cathode cavity 225 can remain in equilibrium with differing flowrates when the anode slurry and the cathode slurry have differingdensities. Furthermore, the geometry of the anode injection nozzle 244and the geometry of the cathode injection nozzle 245 is such that theinjection nozzles 244 and 245 substantially balance the pressure of aportion of the anode cavity 215 and cathode cavity 225 in which they aredisposed.

With a desired amount of anode slurry and cathode slurry transferred tothe anode cavity 215 and the cathode cavity 225, the anode injectionnozzle 244 and the cathode injection nozzle 245 can be retracted throughthe ports 212 and 222, respectively. In this manner, the ports 212 and222 can be sealed and the battery cell 210 can be tested.

While the system 200 describes a method for manufacturing anelectrochemical cell using injection nozzles, in other embodiments, anelectrochemical cell can be manufactured using any suitable method. Forexample, FIG. 6 illustrates a method 360 for manufacturing anelectrochemical cell (e.g., any of those described herein), according toan embodiment. The method 360 includes discharging a semi-solidsuspension electrode material through an extrusion die slot to form anelectrode, at 361. The extrusion die can be such that the shape of theslot substantially corresponds to a geometry of an electrode compartmentof the electrochemical cell. In this manner, the extruded semi-solidsuspension electrode material (e.g., an anode slurry and/or cathodeslurry) can have a geometry that substantially corresponds to theelectrode chamber.

The method 360 includes transferring the formed electrode to theelectrode compartment, at 362. In some embodiments, the extruded slurrycan be gravity fed into the electrode compartment. In such embodiments,the physical properties of the electrode slurry can be such that theextruded slurry resists cross-sectional shape change and/or flexuraldistortion under the gravitational force (e.g., under hanging massconditions). Thus, the shape of the extruded slurry can be such that aminimal tolerance exists between an outer surface of the extruded slurryand an inner surface of a set of walls defining the electrodecompartment. In some embodiments, the method 360 can optionally includecoating the extruded electrode slurry with any suitable material thatcan substantially enhance the transferring of the extruded slurry intothe electrode compartment (e.g., an oil or the like to reduce stickingof the extruded slurry).

The method 360 can further include transferring an electrolyte to theelectrode compartment when the electrode slurry is disposed therein, at363. In this manner, the electrolyte can fill void regions within theelectrode compartment defined between the electrode slurry and the wallsdefining the electrode compartment. With the electrolyte disposed withinthe electrode compartment, the electrode cell can be sealed. The method360 can optionally include utilizing a post-processing method (e.g.,mechanical vibration, sonication, axial acceleration, centrifugalacceleration, or the like) such that the electrolyte and the electrodeslurry mix to define a substantially uniform suspension within theelectrode compartment, at 364.

FIG. 7 is a flowchart illustrating a method 460 for manufacturing anelectrochemical cell (e.g., any of those described herein), according toan embodiment. The method 460 includes filling an electrode compartmentwith an electrode material in powdered form, at 461. The powderedelectrode material can be composed of at least an active material (e.g.,any of those described herein) and a conductive material (e.g., carbon).With the powdered electrode material disposed within the electrodecompartment, the electrode cell can be placed in fluid communicationwith an electrolyte reservoir, at 462. In some embodiments, theelectrolyte reservoir can be an electrolyte vapor-containing reservoirand the electrode cell can be at least partially disposed therein (e.g.,some or all of the electrode cell can be disposed therein). Expandingfurther, the electrolyte vapor disposed within the electrolyte reservoircan be maintained at a temperature that is substantially greater than atemperature of the electrode compartment (e.g., the electrodecompartment can be actively cooled). Similarly stated, a volume outsidethe electrode compartment can be at a substantially greater temperaturethan a volume inside the electrode compartment.

The method 460 further includes transferring a portion of theelectrolyte vapor into the electrode compartment such that theelectrolyte vapor condenses to liquid form within the electrodecompartment, at 463. With the electrode compartment filled (e.g., by thepowdered electrode material and the electrolyte), the method 460 caninclude sealing the electrode cell, at 464. The method 460 canoptionally include utilizing a post processing method (e.g., mechanicalvibration, sonication, axial acceleration, centrifugal acceleration, orthe like) such that the electrolyte and the powdered electrode mix todefine a substantially uniform suspension within the electrodecompartment, at 465.

Referring now to FIG. 8, a system 500 for manufacturing anelectrochemical cell is illustrated, according to an embodiment. Thesystem 500 includes a set of electrochemical cells 510 disposed on aportion of a centrifuge 551. The electrochemical cells 510 can be any ofthose described herein. The centrifuge 551 includes a center portion552, an outer portion 553, and a set of reservoirs 554. As shown in FIG.8, the electrochemical cells 510 can be disposed at the outer portion553 of the centrifuge 551 and can be in fluid communication with thereservoirs 554. For example, the electrochemical cells 510 can include aport (not shown) that is in fluid communication with the reservoirs 554.Expanding further, the electrochemical cells 510 can be disposed at anoutboard position on the centrifuge 551 relative to the reservoirs 554.

The reservoirs 554 can contain an electrode formulation or any portionthereof. For example, in some embodiments, the reservoirs 554 caninclude an anolyte and/or a catholyte, such as those described herein.In this manner, the centrifuge 551 can be rotated about an axis (notshown) defined by the inner portion 552 such that the electrode istransferred from the reservoirs 554 into the electrochemical cells 510by the centripetal acceleration of the electrochemical cells 510. Insome embodiments, the electrochemical cells 510 can be pre-disposed withan electrode in powdered form and the reservoirs 554 can contain anelectrolyte. In such embodiments, the electrolyte can be transferred tothe electrochemical cells 510, and mixing of the powdered electrode withthe electrolyte can be facilitated by, the centripetal acceleration ofthe electrochemical cells 510. In some embodiments, the electrochemicalcell 510 and/or the centrifuge 551 can be vibrated to facilitate themixing of the powdered electrode and the electrolyte. In otherembodiments, sonication can be used to facilitate mixing.

During any of the manufacturing methods described herein, transferringof an electrode material (e.g., a slurry) into an electrode compartmentcan be such that a separator (e.g., an ion permeable membrane) and/or acurrent collector at least partially defining the electrode compartmentcan be deformed. Such deformation can result in a generally unstableconfiguration as areas available for flow opposite the deformationincrease, thereby leading to higher flow partitioning, increaseddeformation, and increased stress in the separator and/or currentcollector. In some embodiments, a post-treatment can be utilized thatcan substantially return the separator and/or current collector to anundeformed configuration. For example, in some embodiments,post-treatment can include full or partial submersion in an ultrasonicliquid bath, anchoring on a vibration table, placement in an acousticchamber or environment, axial acceleration (e.g., in the direction ofthe thickness of the electrochemical cell), affixation of piezoelectriccomponents to the cell hardware, heating and/or cooling, or anycombination thereof. In such embodiments, the post-treatment can be suchthat the separator and/or current collector return to a substantiallyplanar configuration. Furthermore, in some embodiments, thepost-treatment can enhance uniformity of the electrode suspension and/orfacilitate the development of an activated carbon network, therebyincreasing electronic conductivity.

Expanding further, in some embodiments, a planetary mixer or similarblending device is used to create a homogenized mixture of at leastactive material, carbon, and electrolyte. In some embodiments, thecarbon included in the suspension can exist as agglomerates. Fluids inthis form are less viscous than fluids wherein the carbon isde-agglomerated, fibrillous, or networked and are therefore, moreflowable (see e.g., FIG. 9).

In some embodiments, the homogenized mixture can be injected into thecavity using any suitable means (which may include other of theembodiments described in this disclosure), and the cell assemblyproceeds. In some embodiments, it can be desirable to subject theelectrochemical cell (e.g., at least the electrode mixture) toultrasonication or other vibratory process such that the carbon mayde-agglomerate and form a fibrillous, electrically conducting network.For example, FIGS. 10A and 10B illustrate a homogenized electrodemixture of 25% volume of LTO 1% volume of Ketjen black electroconductivecarbon black (“Ketjen”) and 25% volume of LTO 2% volume of Ketjen,respectively, prior to sonication. The homogenized mixtures can besubstantially flowable and can be disposed within an electrochemicalcell. After being disposed within the electrochemical cell the electrodemixtures can be subjected to sonication such that an activated carbonnetwork develops therein. For example, FIGS. 10C and 10D illustrate the25% volume of LTO 1% volume of Ketjen mixture and the 25% volume of LTO2% volume of Ketjen mixture, respectively, after one minute in asonication bath. As shown, the carbon forms a de-agglomerated activenetwork and thus, the electronic conductivity of the electrode mixturesare increased.

In some embodiments, other post-treatment processes can be utilized inconjunction with or separate from sonication. For example, increasingtemperature, exposure to light, and/or imposition of electric currentand/or magnetic fields can be used to produce similar effects, and canbe collectively optimized for the purpose according to the types ofmaterials in use. In other embodiments, it can be desirable to have anactivated carbon network within the electrode prior to flowing theelectrode into an electrode compartment. In such embodiments, thepost-treatments described above can be used to enhance the flow of theelectrode. In some embodiments, a vacuum can be applied to a portion ofthe electrode compartment to facilitate the flow of the electrodematerial.

In some embodiments, deformation of a separator and/or current collectorcan be minimized by varying flow rates of an electrode material into anelectrode compartment of an electrochemical cell. For example, in someembodiments, an anode compartment and cathode compartment can be filledconcurrently such that pressures within the anode compartmentsubstantially balance pressures within the cathode compartment, therebyminimizing deformation of the separator disposed therebetween. However,in some embodiments, the anolyte and catholyte (e.g., the electrodematerial) can have different rheological properties such that pressuregradients of the anolyte and catholyte are different and varied. In suchembodiments, the flow rate of the anolyte and/or the catholyte can bevaried such that the pressure gradients are substantially equal. Inother embodiments, any suitable material can be added to the anolyteand/or catholyte to substantially change the rheological properties ofthe anolyte or the catholyte. The graph of FIG. 11 illustrates arelationship between a pressure and a pumped volume of the electrode. Asshown, the feed pressure of the anolyte and the catholyte increaseduring the fill, each to over 100 psi once the cell is full. However, byfilling the compartments concurrently, the differential pressure acrossa compartment-bounding element (e.g., separator or current collector) isreduced, thus reducing deformation of the compartment-bounding elementduring the fill process.

In some embodiments, deformation of a separator and/or current collectorcan be minimized by including support structures within theelectrochemical cell. For example, FIGS. 12A and 12B illustrate portionsof an electrode cell 611 (e.g., an anode cell or a cathode cell),according to an embodiment. As shown in FIG. 12A, the electrode cell 611includes a current collector 613 having multiple support structures616A. The support structures 616A can be configured to extend from thecurrent collector 613 towards a separator (not shown in FIGS. 12 and12B). In this manner, the support structures 616A can engage theseparator to provide support during a fill process.

As shown in FIG. 12 A, the support structures 616A can be a pin-chuckstyle support (e.g., elongates extending from the current collector). Inother embodiments, a support structure can be any suitable supportmember such as, for example, posts or ridges. For example, FIG. 12Billustrates a support structure 616B wherein the elongates substantiallyform a point. While shown as being monolithically formed with thecurrent collector 613, in some embodiments, a support structure can becoupled to a current collector, monolithically formed with a separator,coupled to a separator, and/or independently disposed within anelectrode compartment.

In use, the support structures 616 (e.g., 616A and/or 616B) can providemechanical support, direct a flow of an electrode during assembly (oroperation in the case of a flow cell), act as a substrate or materialanchor, and/or facilitate enhanced electrical conductivity. In someembodiments, the sharp cornered supports can lead to solid phasesegregation during a fill process. In such embodiments, the supportstructures can act like a filter such that a liquid phase emerges at theflow front (as shown in FIG. 13). Accordingly, the support structure canbe designed to optimize the flow scheme of the electrode material and/orpost-processing steps can be suitably selected to provide compositionaluniformity of the suspension throughout the electrode compartment duringfill and/or flow. In some embodiments, materials and surfaceroughness/treatments can be selected to modulate flow slip over thesupport structures. In some embodiments, the process conditions (e.g.,flow rate, temperature, etc.) can be selected to maintain homogeneity.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. For example, while the embodiments herein describeelectrochemical devices such as, for example, lithium ion batteries, thesystems, methods and principles described herein are applicable to alldevices containing electrochemically active media. Said another way, anyelectrodes and/or devices including at least an active material (sourceor sink of charge carriers), an electronically conducting additive, andan ionically conducting media (electrolyte) such as, for example,batteries, capacitors, electric double-layer capacitors (e.g.,ultracapacitors), pseudo-capacitors, etc., are within the scope of thisdisclosure. Furthermore, the embodiments can be used with non-aqueousand/or aqueous electrolyte battery chemistries.

Where methods and steps described above indicate certain eventsoccurring in certain order, those of ordinary skill in the art havingthe benefit of this disclosure would recognize that the ordering ofcertain steps may be modified and that such modifications are inaccordance with the variations of the invention. Additionally, certainof the steps may be performed concurrently in a parallel process whenpossible, as well as performed sequentially as described above.Additionally, certain steps may be partially completed and/or omittedbefore proceeding to subsequent steps.

While various embodiments have been particularly shown and described,various changes in form and details may be made. For example, althoughvarious embodiments have been described as having particular featuresand/or combinations of components, other embodiments are possible havingany combination or sub-combination of any features and/or componentsfrom any of the embodiments described herein. The specificconfigurations of the various components can also be varied.

1-54. (canceled)
 55. A method of forming an electrode, the methodcomprising: receiving, at an extruder and from a reservoir, a flow of anelectrode material; transferring the electrode material, via an openingof the extruder, to a surface of a substantially planar currentcollector; and removing a portion of the electrode material to form theelectrode.
 56. The method of claim 55, further comprising: disposing asupport structure on the surface of the current collector, the supportstructure defining an opening configured to receive the electrodematerial.
 57. The method of claim 56, wherein the support structure isconfigured to provide mechanical support of the electrode materialduring transferring of the electrode material.
 58. The method of claim55, wherein the transferring the electrode material is in a directionthat is normal to the surface of the current collector.
 59. The methodof claim 55, wherein the opening of the extruder is at least one of ahanger die sheet extrusion die, a winter manifold sheet extrusion die,and a profile-style sheet extrusion die.
 60. The method of claim 55,wherein the extruder includes a plurality of conduits.
 61. The method ofclaim 55, further comprising: applying pressure to the electrodematerial during transferring of the electrode material.
 62. The methodof claim 55, wherein the electrode material is gravity-fed duringtransferring of the electrode material.
 63. The method of claim 55,wherein the extruder is at least one of heated and vibrated duringtransferring of the electrode material.
 64. The method of claim 55,wherein the opening of the extruder has a shape that corresponds to ageometry of the electrode.
 65. The method of claim 55, wherein theelectrode material is a mixture that includes an active material, aconductive material and an electrolyte.
 66. The method of claim 55,wherein the extruder is monolithically formed.
 67. A method of formingan electrode, the method comprising: receiving, at an injection tool andfrom a reservoir, an electrode material; flowing the electrode material,via a nozzle of the injection tool, onto a surface of a substantiallyplanar current collector to define an electrode; and mechanicallypost-processing the electrode to make the electrode uniform.
 68. Themethod of claim 67, wherein the electrode material comprises asubstantially uniform suspension.
 69. The method of claim 67, whereinthe electrode material comprises a slurry.
 70. The method of claim 67,wherein the nozzle comprises a slot.
 71. A method of forming anelectrode, the method comprising: receiving, at an injection tool andfrom a reservoir, an electrode material; discharging the electrodematerial, via a movable nozzle of the injection tool, onto a surface ofa substantially planar current collector to define an electrode; andsubsequently removing a portion of the electrode.
 72. The method ofclaim 71, further comprising flowing the electrode material onto thesurface of the current collector via a port.
 73. The method of claim 71,wherein the electrode has a polygonal shape.
 74. The method of claim 71,wherein the electrode material is at least one of a flowable anodicsemi-solid and a flowable cathodic semi-solid.